Rheostat.



H. J. WIEGANU.

RHEOSTAT. 1 APPLICATION HLED MAR. 8. 1915.

1,267,726. Patented May 28,1918.

2 SHEETS-SHEET 1.

H. J. WIEGANQ.

BHEOSTAT.

APPLSCATIOH FILED HAR- 3.1915- 1,267,726. Patented May 28,1918T 2 SHEETSSHEET 2.

UNITED STATES PATENT OFFICE.

HENRY I. WIIGAND, OI INIIIZIWAIIVIIEE WISCONSIN, ASSIGNOB TO THE CUTLER-HAMMER m. 00., O1 MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

BHEOSTAT.

Specification of Letters Patent.

To all whom it may concern:

Be it known that I, HENRY J. WIEGAND, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Rheostats, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

This invention relates to rheostats 'and more particularly to such devices of the type known as field regulators.

One of the objects of the invention is to simplify the construction and reduce the manufacturing cost of such regulators.

A further object is to provide an improved rheostat having characteristics of functional advantage and structural superiority.

Other objects will be in part evident and in part pointed out hereinafter in connection with the description of an embodiment of the invention illustrated in the accompanying drawings, in which Figure 1 is a front elevational view of a rheostat.

Fig. 2; is a sectional view thereof on the line 2-2 of Fig. 1.

Fig. 3% is a rear elevational view of the same partially in section.

Fig. 4 is a perspective view of one part.

Fig. 5 is a fragmentary sectional view.

Fig. 6 is a side elevational view of the rheostat and supporting panel therefor.

Fig. '2' is a perspective view of an auxiliary part, and

Figs. 8 and 9 are, respectively, central sectional and rear elevational views of an operating handle.

The device illustrated comprises in general, a base 1 having a resistance element 2 connected in sections with fixed contacts to be engaged by a controlling contact arm 3 for varying the amount of resistance included in the regulated circuit.

Referring more specifically to the drawing, the base 1, typically of soapstone, is fiat and rectangular in shape and carries on its frontface a series of fixed contacts i arranged ahout the circumference of a circle. Each of these fixed contacts, as shown in Fig. 4, comprises a headed member consisting of a shank 5 having two fiat prongs and a cap or button 4 beaded thereon- In practice it has been found that ordinary paper fasteners of a well known type may be utlhzed for this urpose, and in such case, the buttons 4 are attened and reinforced by soldering. The contact shanks 5 being of pliable metal, are advantageously embedded 1n lead reinforcing slugs 6, the same being then seated in circular apertures 7 provided therefor in the .base. The free projecting ends of the contacts afford means to anchor the contacts in place and also serve for connectlon' with the sinuous reflexed resistance wire 2 which is mounted on the rear surface of the base. Said resistance wire is arranged in a series of radially disposed convoluted loops, each of which is caught over a fixed pin 8 at its periphery and is clamped within a folded extremity 9 of one of the contact prongs. The other contact prong is also folded flatwise against the base for anchoring the contact as above indicated, both of the prongs thus lying substantially flush with the base. It is to be noted furthermore, that the double or multipart flexible shank of the contacts enables the latter to be positioned and secured as a step in the assembly of the parts and prior to mounting the resistance. While the contacts and the resistance element are thus insured firm retention on the base 1, there is also provided a layer 10 of insulating cement which protectively covers the resistor 2 and the bent extremities of the contacts. This insulating layer 10 is, however, applied in a very thin coating so that the gross thickness of the device may be minimized. Thus it will be seen that the stationary parts of the rheostat constitute a structural unit of noteworthy cheapness and simplicity and moreover, that the rear of the base is entirely clear whereby free atmospheric circulation is permitted to carry ofl" any heat generated;

The rheostat operating member comprises a hand grip 11 preferably of molded insulating material and is rotatably mounted on the base concentrically with the series of contact buttons 4. The radially projecting contact arm 3 is secured to the hand grip 11 and resiliently bears upon the contact buttons. For attaching the arm 3 to the operating handle, the latter has one or more threaded taps 12 molded in the insulation to receive screws 13 extendin through p ures in the con a a m. .e hand Patented May 28, 1918. l

grip is also provided with a central bore 14 and is mounted upon the base by means of a bolt 15 which extends through said central bore and the base and maintains the inner end of the arm 3 in engagement with a bearing plate 16 fixed centrally on the base. The contact arm is electrically connected, as through the bolt 15, with one terminal 17 located at the edge of the base, while the other terminal 18 connects with the contact button 4 on which the arm '3 rests in initial position, that is, against one side of a non-current carrying pin 19 provided to limit movement of the operating member. The terminals 17 and 18 also extend through the base and are provided at both the front and rear thereof with con ductor attaching means 20 whereby wiring connections may be readily e-fi'ected from either face. When the rheostat is connected in circuit it will be obvious that the path of current is from one terminal to the arm 3 and through varying amounts of the resistance 2, in accordance with the position of the operating member, tothe opposite terminal.

The rheostat is designed for either front or rear board mounting and is provided at its corners with attaching bolts 21 having spacing sleevs 22 thereon. It will be noted that the protective insulating cement 10 on the rear of the base is applied to leave the four corners thereof clear for said supporting bolts. When the rheostat is mounted in the rear of a panel, such as indicated at 23, there is provided an auxiliary operating hand grip 24 which is operatively connected with the hand grip 11 by a spindle 25. For the purpose of economy, the auxiliary handle 24 and the main handle 11 are identical save that the former carries a com pressible tube 26 to receive the spindle 25 and a set screw 27 to lock the handle on said spindle. Each operating knob is also provided with a key slot 28 in its outer face adapted to receive a key 29 on the spindle 25 for interlocking said parts to rotate together. When the rheostat is mounted as shown in full lines in Fig. 6, the spindle 25 is held keyed to the knob 11 by an enlarged shoulder 30 which bears against the rear of the panel. In the same manner the outer hand grip 24 is maintained in position by its clamping set screw connection with the spindle.

It will be apparent that in the front board mounting as indicated in dotted lines in Fig. 6, both the auxiliary handle 24 and the spindle 25 are dispensed with and that the spacing sleeves 22 on the bolts 21 are transferred to the opposite side of the base. In both cases therefore, the clampingnuts and projecting ends of the attaching bolts are disposed behind the supporting panel. The hand grip 11 is also provided with a flange, 31 adjacent the contact arm which serves to protect the operators hand against accidental contact with any of the current carrying parts.

It is to be noted that the various elements descr1bed are capable of cheap. manufacture and assembly and that the device as a whole is both sturdy and compact. As above set forth, also, the rheostat is equally adaptable for mounting on the front or rear of a supporting panel, a feature of great practical advantage. Moreover, the device may be readily changed from one mounting to the other and, due to its minimum dimensions, occupies but little space in either case.

What I claim as new and desire to secure base provided with a series of spaced apertures therethrough, a resistance arranged on the rear of said base and parallel thereto and a plurality of contacts having flat pliable portions extending through said apertures and folded flatwise at the rear thereof to engage and hold said resistance.

3. A rheostat having a flat base provided with a series of apertures therethrough, a resistance mounted on said base and a plurality of contacts connected to said resistance, each of said contacts having a headed portion seated on the'front face of said base and a pliable shank extending through one of the apertures in said base and overturned to engage the rear face of said base for fastenin 4. i rheostat having a flat base provided with a series of apertures therethrough, .a resistance mounted on the rear face of said base, a plurality of contacts each comprising a headed portion seated on the front of said baseand a multipart pliable shank passing through one of the apertures in said base and overturned at the rear of said base for fastening and for electrical connection with said resistance and a coating of insulating cement adhering to the rear face of said base and embedding said resistance and the over turned portions of said contacts.

5. In combination, a rheostat having a base and a regulating resistance thereon and panel attaching means for said base readily reversible with respect thereto for mounting the rheostat in front or rear of a panel without reversing said base.

6. A rheostat having a base and a resistance thereon, panel attaching bolts penetrating and base and spacing members assotransferciated with said bolts and readily d b sai ase,

able from the front to the rear 0 for the purpose set forth.

7. In combination a panel, a rheostat for front or back mountin thereon having a rotatable contact arm, a and grip for operating the same, and extension operating means for said contact arm comprising a second hand grip and a spindle keyed to said first mentioned hand grip.

8. In combination a panel, a rheostat for front or back mounting thereon having a rotatable contact arm, a hand grip for operating the same and extension operatin means for said arm comprising a second hand grip, a spindle detachably keyed to said first mentioned hand grip and means for detachably locking said second mentioned hand grip to said spindle.

HENRY J. WIEGAND.

Witnesses:

H. A. Snoowrox, J. W. Wanmnm. 

